Classifications

B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes

B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds

B01J8/06—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds in tube reactors; the solid particles being arranged in tubes

B01J8/067—Heating or cooling the reactor

C—CHEMISTRY; METALLURGY

C07—ORGANIC CHEMISTRY

C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS

C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides

C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation

C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen

C07C51/25—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of unsaturated compounds containing no six-membered aromatic ring

C07C51/252—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of unsaturated compounds containing no six-membered aromatic ring of propene, butenes, acrolein or methacrolein

Abstract

A process for the catalytic gas-phase oxidation of acrolein to acrylic acid in a multiple contact tube fixed-bed reactor, with only one heat transfer medium being circulated through the space surrounding the contact tubes, at elevated temperature over catalytically active multimetal oxides at an acrolein conversion on a single pass of >/= 95 mol% and a selectivity of acrylic acid formation of >/= 90 mol%, in which the heat exchange medium on the one hand is passed longitudinally, viewed over the reaction vessel, to the contact tubes in cocurrent to the reaction gas mixture through the multiple contact tube fixed-bed reactor, and, on the other hand, has, within the reaction vessel, due to a successive arrangement, along the contact tubes, of deflecting discs which leave open cross-sections free, a superposed crossflow in such a way that, in longitudinal section through the contact tube bundle, a meander-like flow of the heat exchange medium results and the flow velocity of the circulated heat exchange medium is here set in such a way that the temperature of the heat exchange medium rises by from 2 to 10 DEG C from the inlet point to the reactor to the outlet point from the reactor.

Sie sind in an sich bekannter Weise erhältlich (siehe z. B. DE-A 43 02 991) und werden üblicherweise in Substanz zu Kugeln, Ringen oder Zylindern geformt oder auch in Gestalt von Schalen katalysatoren, dh mit der Aktivmasse beschichteten vorgeformten inerten Trägerkörpern, eingesetzt. They are obtainable in a known manner (see, for. Example, DE-A 43 02 991) and are usually shaped in substance to give spheres, rings or cylinders or catalysts in the form of shells, that is coated with the active mass preformed inert support bodies used.Selbstverständlich können sie aber auch in Pulverform als Katalysatoren angewendet werden. Of course, but they can also be used in powder form as catalysts.

Bei erfindungsgemäß besonders vorteilhaften Verfahrensvarianten sind möglichst viele der Zusatzmerkmale a bis g simultan erfüllt. In accordance with the invention particularly advantageous process variants as many of the additional features a to g are met simultaneously.Besonders bevorzugt sind alle Zusatzmerkmale a bis g simultan er füllt. Particularly preferably all additional features a to g, it simultaneously fills.Es wird diesseits davon ausgegangen, daß insbesondere bei der letztgenannten Verfahrensweise ein Temperaturverlauf in der Kontaktrohrwand längs eines einzelnen Kontaktrohres erzielt wird, bei dem die Temperatur der Kontaktrohrwand bis zu einem Acrolein umsatz von 20 bis 50 mol.-% im wesentlichen konstant ist und anschließend bis zum Rohrende um 2 bis 10°C anwächst. It is considered on this side of it, that a temperature variation in the contact tube wall along an individual contact tube is achieved especially in the case of the latter method, in which the temperature of the contact tube wall up to an acrolein conversion of from 20 to 50 moles is constant .-% generally, and then to increases by 2 to 10 ° C the tube end.Es wird diesseits ferner davon ausgegangen, daß bei dieser Verfahrens weise im vorgenannten Umsatzbereich auch über den Reaktorquer schnitt im wesentlichen einheitliche Wandtemperaturen der Kontaktrohre vorliegen. It is believed this side further from the fact that in this method as in the above conversion range even over the reactor cross-section are in essentially uniform wall temperatures of the contact tubes.

Ganz generell wird man versuchen die Anzahl an verwendeten Um lenkblechen zu beschränken. Quite generally will try the number of used to fork steering To limit.Anwendungstechnisch zweckmäßig be trägt diese Anzahl 3 bis 9. Appropriately from an application be wearing this number 3 to 9.

Im übrigen eröffnet das erfindungsgemäße Ergebnis die Option, entweder bei vorgegebener Raum-Zeit-Ausbeute aufgrund der günstigeren Heißpunktlage eine längere Standzeit der Katalysatorbeschickung zu erreichen, oder bei vorgegebener Standzeit durch Erhöhung der Belastung eine erhöhte Raum- Zeit-Ausbeute zu erzielen. In other income to the invention opens the option either for a predetermined space-time yield due to the favorable hotspot able to achieve a longer service life of the catalyst charge, or at specified service life by increasing the load to achieve an increased space-time yield.

2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Temperatur des Wärmeaustauschmittels von der Eintrittsstelle in den Reaktor bis zur Austrittsstelle aus dem Reaktor um 3 bis 8°C ansteigt. 2. The method according to claim 1, characterized in that the temperature of the heat exchange means to the outlet point increases from the point of entry into the reactor from the reactor 3 to 8 ° C.

3. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Temperatur des Wärmeaustauschmittels von der Eintrittsstelle in den Reaktor bis zur Austrittsstelle aus dem Reaktor um 4 bis 6°C ansteigt. 3. The method according to claim 1, characterized in that the temperature of the heat exchange means to the outlet point increases from the point of entry into the reactor from the reactor at 4 to 6 ° C.

Production of acrolein or acrylic acid involves absorption of propane and propene from a gas mixture followed by desorption and oxidation, with no catalytic dehydrogenation of propane and no added oxygen

Heterogeneously catalyzed gas phase partial oxidation of organic compound in fixed catalyst bed involves recovering quality of catalyst bed by replacing its portion, with a catalyst having activity lower than that of the replaced catalyst

Preparation of a catalyst, useful in the heterogeneously catalyzed partial gas phase oxidation of acrolein to acrylic acid, comprises attaching one of the active mass to the surface of the carrier body with the help of a binding agent

Thermal separation between at least a gas ascending- and a liquid containing at least a (meth)acrylic-monomer descending respectively in separating column, accomplished in a separation effective installation containing separating columns

Production of acrolein or acrylic acid from propane, involves partial gas-phase dehydrogenation, removal of hydrogen and partial gas-phase oxidation of propene with nitrogen as diluent, and recycling of unreacted propane